Qantas has pushed back the restart date for most of its international network after the federal budget revealed Australia’s border will likely remain shut until the middle of next year.

In the latest blow to its overseas flying plans, Australia’s national airline said on Tuesday it would cancel all international flights other than to New Zealand scheduled from October 31 through to December 20.

“We remain optimistic that additional bubbles will open once Australia’s vaccine rollout is complete to countries who, by then, are in a similar position, but it’s difficult to predict which ones at this stage,” a Qantas spokesman said in a statement.

“We will keep reviewing these plans as we move towards December and circumstances evolve.”

In January, Qantas and its budget arm Jetstar were selling tickets to most to international destinations from July 1, but in February pushed that back to October as delays to Australia’s COVID-19 vaccine rollout became apparent.

In Tuesday’s federal budget, the government said inbound and outbound international travel would remain low until the middle of 2022, followed by “a gradual recovery in international tourism”.

“The rate of international arrivals will continue to be constrained by state and territory quarantine caps over 2021 and the first half of 2022, with the exception of passengers from safe travel zones,” the budget states.

Qantas said its call centres were flooded with inquiries and that it would directly contact customers who had international bookings beyond New Zealand between October 31 and December 19.

All customers on Qantas and Jetstar flights cancelled due to the changes could choose to receive a full refund for their fare, a Qantas spokesman said.

Australia’s $60 billion tourism sector has hit out at the Morrison government’s second pandemic budget, saying that operators will go bust before Australia reopens to international visitors.

Tourism and Transport Forum chief executive Margy Osmond said the sector needed more certainty from the government on its plan for opening up than the vague outline given in the budget so operators could prepare.

Treasurer Josh Frydenberg told the ABC’s 7.30 program that the budget paper’s assumptions around international travel were “cautious”.